The invention relates to desensitizing teeth.
The dentin layer in a tooth generally contains channels, or tubules, extending from the pulpal surface to the peripheral surface located underneath the enamel and cementum. Loss of enamel and/or gingival recession accompanied by loss of cementum may expose these tubules in the dentin. It has been theorized that these exposed tubules are responsible, in part, for hypersensitivity to mechanical pressure or hot or cold fluids.
The problem of hypersensitive teeth is well-recognized, and various treatments have been proposed in the art. Pashley et al., U.S. Pat. No. 4,057,021, describes desensitizing hypersensitive teeth by applying an aqueous solution of alkali metal salts and ammonium oxalate to the surface of the teeth. Kim, U.S. Pat. Nos. 4,631,185 and 4,751,072 describes desensitizing teeth by treatment with potassium salts. Neirinckx, U.S. Pat. No. 4,990,327, describes desensitizing teeth with strontium ion and fluoride ion. Mason, U.S. Pat. No. 4,992,258, describes desensitizing teeth by applying a dentifrice including a montmorillonite clay. Lutz, U.S. Pat. No. 4,011,309, describes a desensitizing dentifrice composition that includes citric acid, sodium citrate, and non-ionic polyol surfactant. Mlkvy et al., U.S. Pat. Nos. 3,888,976 and 3,772,431 describe using a zinc or strontium ion containing astringent-desensitizing agent in an effervescent mouthwash tablet. Hodosh, U.S. Pat. No. 3,863,006, describes desensitizing teeth with a nitrate salt. Svajda, U.S. Pat. No. 3,689,636, describes desensitizing teeth with solutions of chloride salts. Rosenthal, U.S. Pat. No. 3,122,483, describes desensitizing teeth with strontium ions. Scheller, U.S. Pat. Nos. 4,634,589 and 4,710,372, describe a dentifrice containing apatite particles for treating hypersensitive teeth. Turesky et al., U.S. Pat. No. 5,250,288, describes desensitizing a hypersensitive tooth by treating the surface of the tooth with charged polymeric particles.